This invention relates to component-carrying circuit boards and, more particularly, to a method for removing conformal covercoats from such boards.
Circuit boards that comprise a substrate on which electronic components are mechanically mounted and electrically interconnected are extensively used in a wide variety of practical applications. To protect the components on the substrate from deleterious environmental factors, it is common practice to cover the entire surface of the component-carrying substrate with a protective coating. Such a protective coating is formed, for example, by spraying a layer of a suitable polymer material onto the surface of the component-carrying substrate.
Each coated circuit board is typically individually tested before connecting it into an overall system assembly. If such testing reveals a fault in the circuit contained on the board, it is necessary to remove the protective coating to gain access to the components and interconnections on the board. Following a repair step, the board is recoated and then retested.
Heretofore, known processes such as plasma cleaning have been employed to remove the protective coating from a faulty circuit board. But, especially because of the extremely long times (many hours) typically required for removal of the coating, such known processes are not, in practice, cost effective.
Thus, it was recognized that a need existed for a more effective way (in particular, a faster way) for removing the conformal coating from a circuit board that is to be repaired. It was apparent that such a removal technique, if available, would be of significant practical importance in contributing to lowering the cost of manufacturing circuit boards and of the systems in which the boards are utilized.